DRAFT UGANDA STANDARD  
  DUS 226 1 
First  Edition  
2020 -mm-dd 
 
 
 Reference number  
DUS 2261 : 2020 
© UNBS 2020   
  
Textiles  — Polyester blended  yarn  — Specification  
 DUS 2261 : 2020  
ii © UNBS 2020  – All rights reserved  
 Compliance with this standard does not, of itself confer immunity from legal obligations  
A Uganda Standard does not purport to include all necessary provisions of a contract. Users are 
responsible for it s correct application  
© UNBS 2020   
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilised in any 
form or by any means, electronic or mechanical, including photocopying and microfilm, without prior written  
permission from UNBS.  
Requests for permission to reproduce this document should be addressed to  
The Executive Director  
Uganda National Bureau of Standards  
P.O. Box 6329  
Kampala  
Uganda  
Tel: +256 41 4 333 2 50/1/2/3  
Fax: +256 41 4 286 123  
E-mail: info@unbs.go.ug  
Web: www.unbs.go.ug  DUS 2261 :2020  
© UNBS 2020  – All rights reserved  iii 
 Contents  Page 
Foreword  ................................ ................................ ................................ ................................ ............................  iv 
1 Scope  ................................ ................................ ................................ ................................ ......................  1 
2 Normative references  ................................ ................................ ................................ ............................  1 
3 Terms and definitions  ................................ ................................ ................................ ...........................  1 
4 Classif ication  ................................ ................................ ................................ ................................ .........  2 
5 Requirements  ................................ ................................ ................................ ................................ .........  3 
4.1 General  ................................ ................................ ................................ ................................ ...................  3 
4.1.1  Blend composition  ................................ ................................ ................................ ................................  3 
4.1.2  Yarn Count  ................................ ................................ ................................ ................................ .............  3 
4.1.2  Yarn twist  ................................ ................................ ................................ ................................ ...............  3 
4.1.3  Moisture regain  ................................ ................................ ................................ ................................ ...... 3 
4.1.4  Yarn appearance  ................................ ................................ ................................ ................................ .... 3 
4.1.5  Freedom from defects  ................................ ................................ ................................ ...........................  3 
4.2 Ring spun single yarn  ................................ ................................ ................................ ...........................  4 
4.3 Rotor spun single yarn  ................................ ................................ ................................ .........................  4 
4.4 Two-fold (doubled yarn) ................................ ................................ ................................ ........................  5 
5 Labelling  ................................ ................................ ................................ ................................ .................  5 
6 Packaging  ................................ ................................ ................................ ................................ ...............  6 
7 Sampling  ................................ ................................ ................................ ................................ ................  6 
Annex A  (normative) Calculation of coun t strength product (CSP)  ................................ .............................  7 
Bibliography  ................................ ................................ ................................ ................................ ........................  8 
 DUS 2261 : 2020  
iv © UNBS 2020  – All rights reserved  
 Foreword  
Uganda National Bureau of Standards (UNBS) is a parastatal under the Ministry of Trade , Industry and 
Cooperativ es established under Cap 327 , of the Laws of Uganda , as amended .  UNBS is mandated to co -
ordinate the elaboration of standards and is  
(a) a member of International Organisation for Standardisation (ISO) and  
(b) a contact point for the WHO/FAO Codex Alimentarius Commission on Food Standards, and  
(c) the National Enquiry Point on TBT  Agreement  of the World Trade Organisation (WTO).  
The work of preparing Uganda Standards is carried out through Technical Committees. A Technical 
Committee is established to deliberate on standards in a given field or area and consists of key stakeholders 
including government, academia, consumer groups, private sector and other interested parties.  
Draft Uganda Standards adopted by the Technical Committee are widely circulated to stakeholde rs and the 
general public for comments. The committee reviews the comments before recommending the draft standards 
for approval and declaration as Uganda Standards by the National Standards Council.  
The committee responsible for this document is Technical Committee UNBS /TC 7, Textiles, Paper and 
Leather Products , Subcommittee SC 1, Textiles and related products . 
 DRAFT UGANDA STANDARD  DUS 2261 : 2020  
 
© UNBS 2020  – All rights reserved  1 
 Textiles — Polyester blended yarn — Specification  
1 Scope   
This Draft Uganda standar d specifies requirements of grey yarn (single and doubled) spun from a blend of 
polyester with cotton or viscose fibre . 
2 Normative references   
The following referenced documents are referred to in the text in such a way that some or all of their content 
constitutes requirements of this document. For dated reference s, only the edition cited applies. For undated 
references, the latest edition of the referenced document (including any amendments) applies.  
ISO 2, Textiles  — Designation  of the direction  of twist in yarns  and related  products   
US ISO 2060, Textiles  — Yarn  from packages  — Determination  of linear  density  (mass  per unit length)  by the  
skein  method   
ISO 2061, Textiles  — Determination  of twist in yarns  — Direct  counting  method   
ISO 2062, Textiles  — Yarns  from packages  — Determination  of single -end breaking  force and elongation  at  
break  using  constant  rate of extension  (CRE)  tester   
ISO 6741 -1, Textiles  — Fibres  and yarns  — Determination  of commercial  mass  of consignments  — Part 1:  
Mass  determination  and calculations   
ISO 6939, Textiles  — Yarns  from packages  —Method   of  test  for  breaking   strength   of  yarn  by  the  skein   
method  
ISO 16549, Textiles  — Unevenness  of textile  strands  — Capacitance  method   
ISO 17202, Textiles  — Determination  of twist in single  spun  yarns  — Untwist/retwist  method   
ASTM D2255, Standard  test method  for grading  spun  yarns  for appearance   
ASTM D5647, Standard  guide  for measuring  hairiness  of yarns  by the photo -electric  apparatus  
3 Terms and definitions   
For the purposes of this document, the following terms and definitions apply.  
ISO and IEC maintain terminological databases for use in standardization at the following addresses:  
— ISO Online browsing platform: available at http://www.iso.org/obp  
3.1  
cotton count (Ne)  
number of hanks (each measuring 768 m or 840 yd) in 453.6 g (or 1 lb)  
2 © UNBS 2020  – All rights reserved  
 3.2  
count lea strength product (CSP)  
product of the lea breaking load in pounds and cotton count  
3.3  
grey cotton yarn  
yarn as it leaves the spinning frame without any bleaching , dyeing or finishing treatment  
Note 1 to entry: The yarn may be waxed or unwaxed  
3.4  
hairiness index  
total length of protruding fibres in the yarn in cm with reference to the sensing length of 1 cm yarn  
3.5  
lea 
continuous length of yarn measuring 109.73 m (120 yd) in the form of a coil having 80 wraps wound on a reel 
of 1.37 m (1.5 yd) girth  
3.6  
breaking load   
maximum load (or force) applied to a specimen in a tensile test carried to rupture  
3.7  
single yarn tenacity  
tensile stress of a single strand at rupture expressed as force per unit linear density of the unstrained 
specimen expressed usually as cN/tex (gf/tex).  
3.8  
tex  
number of grams per kilometre of yarn  
3.9  
ring spun yarn  
yarn spun on a system employing flat top cards and roller drafting assemblies with or without aprons on 
drawing, roving and ring frames  
3.10  
rotor spun yarn  
yarn spun on an open -end spinning machine wherein the individualization and assembling of fibres are done 
and the real twist is effected by a rotor  
3.11 
doubled y arn 
yarn in which two or more single ya rns are twisted together in one or two operations.  
4 Classification  
The ring spun polyester blended y arn shall be classified as below :  
a) PB 45 The polyester content in the blended yarn betwee n 40 to 55 percent.  
b) PB 65 The polyester content in the blende d yarn between 55 to 70 percent.  
c) PB 80 The p olyester content in the blended yarn above 70 percent  DUS 2261 : 2020  
© UNBS 2020  – All rights reserved  3 
 5 Requirements  
4.1 General  
4.1.1  Blend composition  
The blend composition of polyester with cotton or viscose fibre shall be as agreed to between the purchaser 
and the manufacturer . However, a tolerance of ± 3 on blend percentage of the major fibre component s hall be 
permissible (see also US 426). 
4.1.2  Yarn Count  
4.1.1.1  The average resultant count of yarn shall be as agreed upon between the purchaser and 
manufacturer.  
4.1.1.2  The coefficient of variatio n of yarn count shall not exceed 3.5 percent  
4.1.1.4  Yarn count shall be determined in accordance with  US ISO 2060.  
4.1.2  Yarn twist  
4.1.2.1  The number of turns per unit length shall be determined in accordance with ISO 2061 or ISO 
17202. The direction for  twist shall be indicated by the capital letter “S” or “Z” as specified in ISO 2.  
4.1.2.2  The average twist shall be within ± 10 percent and ± 5 percent of the specified value for single 
spun yarn and doubled yarn respectively  
4.1.3  Moisture regain  
Unless  otherwise agreed to between the purchaser and manufacturer, the moisture regain shall not exceed 
8.5 percent when determined in accordance with ISO  6741 -1. 
4.1.4  Yarn appearance  
When determined in accordance with ASTM  D2255 , the average black board appear ance (5 boards) shall be 
at least of Grade D. In case of yarn counts coarser than 98 tex (6s), this shall be as agreed to between the 
purchaser and the manufacturer.  
4.1.5  Freedom from defects  
The yarn on cones/cheeses shall be free from the following defe cts: 
a) stitches of more than 2.5 cm in length at the base;  
b) excessive stitches at the nose;  
c) soft cones or cheeses;  
d) prominent stains inclusive of chalk and other markings;  
e) cut threads;  
f) absence of tail end where it is required and the length of the tail -end sho uld not be less than 30 cm;  
g) entanglement;  
h) presence of hard waste;   
4 © UNBS 2020  – All rights reserved  
 i) ribbon formation;  
j) drum cuts;  
k) count mix up.  
4.2 Ring spun s ingle yarn  
4.2.1 The ring spun single grey yarn shall comply with the requirem ents given in Table 1 . 
4.2.2  When determined in accord ance with ISO 6939, t he coefficient of variation of lea breaking load shall 
not exceed 10.0 percent  
Table 1  — Performance requirements of ring spun polyester blended yarn  
Parameter  Requirement  
Test 
Method  ≥ 25 
tex (≤ 
24s) 16 – 25 
tex 
(24s – 
36s) 12 – 16 
tex 
(36s – 
50s) 8 – 12 
tex 
(50s – 
75s) 8 tex 
(75s) 
and 
finer 
CSP for 
polyester/Cotton 
blends, Min.  PB 45  2 300  2 300  2 200  2 100  2 000   
 
Annex A  PB 65  2 500  2 500  2 400  2 300  2 100  
PB 80  - - - - 2 200  
CSP for 
polyester/Viscose 
blends, Min.  PB 45  2 500  2 500  2 400  2 300  2 200  
PB 65  2 650  2 650  2 550  2 450  2 250  
PB 80  - - - - 2 300  
Unevenness, %, Max  14.5 14.5 15.5 16.0 18.0 ISO 
16549  
Imperfections/Km  
Thin 
Thick  
Neps  
Total   
75 
200 
130 
405  
75 
200 
130 
405  
150 
225 
200 
575  
275 
250 
250 
775  
500 
300 
300 
1 100  ISO 
16549  
NOTE  The unevenness percentage (U %) and the imperfections per Km of the yarn on 
packages shall not exceed the values given in Tabl e 2 when tested at a speed of 5 0 m/mi n 
and at sen sitivity of -50%, +30% and +3 0% for thin places, thick places and neps 
respectively  
 
4.3 Rotor spun single yarn  
The rotor spun single grey yarn  shall comply with the requirem ents given in Table 2 . 
Table 2 — Performance requirements of rotor spun polyester  blended yarn  
Parameter  Requirement  Test Method  
Polyester viscose 
(48%/52%)  Polyester cotton 
(67%/33%)  
15s 20s 15s 20s 
Rkm, g/tex, min.  10.5 14.0 17.0 22.0  DUS 2261 : 2020  
© UNBS 2020  – All rights reserved  5 
 Unevenness (U%)  10.5 11.5 11.0 11.5 ISO 16549  
Imperfections/Km  
Thin 
Thick  
Neps  
Total   
6 
24 
41 
71  
14 
31 
59 
104  
8 
26 
41 
75  
21 
44 
69 
134 ISO 16549  
NOTE  The unevenness percentage (U %) and the imperfections per Km of the yarn on 
packages shall not exceed the values given in Tabl e 2 when tested at a speed of 40 0 m/min 
and at sensitivity of -50%,  +50% and +200% for thin places, thick places and neps 
respectively  
4.4 Doubled yarn  
4.4.1 The single yarn used for producing doubled yarn shall satisfy the requirements specified in 4.1  and 
either 4.2 or 4.3.  
4.4.2  The count lea strength product (CSP) of  doubled yarn shall not be less than the value calculated by 
the following relationship:  
 
4.4.3  The coefficient of variation of the lea count shall not exceed 2.0 percent  
4.4.4  The coefficient of variation of the lea breaking load shall not exceed 7.0 per cent.  
5 Labelling  
5.1  Each cone or cheese of yarn shall be marked with the following:  
a) blend composition ; 
b) count of yarn in ‘N e’ or ‘tex;’  
c) lot number;  
d) manufacturer’s name, trademark or other means of identification;  
e) spinning method used, e.g. ring or rotor;  
f) individual package size/mass;  
g) end use of yarn, e.g. weaving  or knitting ; 
h) whether waxed or unwaxed;  
i) packaging and storage conditions.  
5.2 Each case containing cones or cheeses shall be marked with the following:  
a) blend composition ; 
b) count of yarn in ‘Ne’ or ‘tex;’ 
c) lot number;   
6 © UNBS 2020  – All rights reserved  
 d) manufacturer’s name, trademark or other means of identification;  
e) gross mass of bale or case;  
f) net mass of bale or case;  
g) packaging and storage conditions; and  
h) country of origin  
6 Packaging  
Cones or cheeses of yarn shall be packaged in su itable packaging materials which shall protect the product 
from damage during transportation, handling and storage. Cones or cheeses shall be packaged in unit 
packages and thereafter into bulk cases.  
7 Sampling  
7.1 In any consignment, the cases containing yarn of the same type and of the same nominal count shall 
constitute a lot.  
7.2 Samples shall be drawn from ea ch lot to determine its conformance  with the requirements of the 
standard.  
7.3  Unless otherwise agreed to between the buyer and the seller, the n umber of cases to be selected from 
a lot sha ll be in accordance with Table 3 . The bales or cases shall be selected at random . 
7.4 In case two or less cases are selected in the sample, at least 10 cones or cheeses shall be drawn at 
random from each of the s elected case. However, in case three or more cases are selected in the sample, at 
least five cones or cheeses shall be drawn at random from each of the selected case.  
Table 3  — Sampling  
Lot Size  Sample Size  
Up to 3  1 
4 – 10 2 
11 – 30 3 
31 – 50 5 
Over 50 8 DUS 2261 : 2020  
© UNBS 2020  – All rights reserved  7 
 Annex A 
 
(normative)  
Calculation of count strength product (CSP)  
CSP is obtained by the following relationship:  
 
Where;  
The breaking load is determined in accordance with ISO 6939  
Cotton count (Ne) is determined in accordance with US ISO 2060  
  
8 © UNBS 2020  – All rights reserved  
 Bibli ography  
[1] IS 171:1993, Textiles — Ring spun grey cotton y arn for weaving — Specification   
[2] IS 13683:2006, Textiles — Ring spun grey cotton yarn — Specification  
[3] IS 13684:2006, Textiles — Rotor spun grey cotton yarn — Specification  
 DUS 2261 : 2020  
© UNBS 2020  – All rights reserved  9 
 Certification m arking  
Products that conform to Uganda standards may be marked with Uganda National Bureau of Standards 
(UNBS) Certification Mark shown in the figure below.  
The use of the UNBS Certification Mark is governed by the Standards Act, and the Regulations made 
thereunder. This mark can be used only by those licensed under the certification mark scheme operated by 
the Uganda National Bureau of Standards and in conjunction with the relevant Uganda Standard. The 
presence of this mark on a product or in relation to a product is an assurance that the goods comply with the 
requirements of that standard under a system of supervision, control and testing in accordance with the 
certification mark scheme of the Uganda National Bureau of Standards. UNBS marked products are 
continually checked by UNBS for conformity to that standard.  
Further particulars of the terms and conditions of licensing may be obtained from the Director, Uganda 
National Bureau of Standards.  
 
 DUS 2261 : 2020    
 
ICS 59.080.20  
Price based on nn pages  
© UNBS 2020 – All rights reserved